A nice feature of the modern social web is that it's modular. You can plug in and customize pre-made pieces of software (often created by other users or companies), and mix and match what works best for you without a lot of technical know-how. Facebook works the same way with apps.

Many Facebook apps are built for casual use, like the social games and quizzes you may see your friends using in their personal feeds. But there are quite a few apps that are ideal for a business Fan Page. These are useful for customizing your page with greater detail, showcasing your content from other social sites, and getting more information from your customers.